Learning Forum

[shubhali_s]

Hello dear all,
we are simulating gas liquid two-phase flow in a bubble column in ANSYS Fluent 2022 R1. We are performing simulations to study mass transfer effects from gas phase to liquid phase for constant small bubble size using Eulerian multiphase model and by enabling MT module. (snapshot is attached)

Many terms from attached panel are not clearly understood for example -

How can we set mass transfer effects using phase interaction in multiphase model?

we are unable to understand the units for the option "constant-rate", there is no specific equation described in Ansys theory guide.

we have tried using constant kla (1/s) value from research paper in reputed journal but it diverged.

By default the panel is set for liquid to gas, so how should we proceed for gas to liquid mass transfer.

Not much detail is given in Ansys theory guide and User guide.
#question
Ansys Fluids

Thank you

[SRP]

Hi,

For details regarding the equations, please refer to fluent theory guide: 14.7.2. Unidirectional Constant Rate Mass Transfer (ansys.com)

Ansys Fluent provides a UDF that you can use to input models for different types of mass transfer, for example, evaporation, condensation, boiling, and so on. Note that when using this UDF, Ansys Fluent will automatically add the source contribution to all relevant momentum and scalar equations. This contribution is based on the assumption that the mass "created" or "destroyed" will have the same momentum and energy of the phase from which it was created or destroyed.

If you are not able to access the link, please refer to this forum discussion: https://forum.ansys.com/forums/topic/using-help-with-links/#latest

Thank you

[Rob]

You may find the sign of the rate (+/-) helps with which way the material is transferred. The From->To is for numerical reasons and to help make sure the formation energy doesn't give the wrong sign.